Valve gearing



H. T. THOMAS VALVE GEARING Dec. 9, 1930.

Filed March 6, 1929 I INVENTOR. 7190mm 1 Tw wma BY A TTORNEY.

Patented Dec. 9, 1930 mam OFFICE,

HORACE T. THOMAS, 0F LANSING, MICHIGAN VALVE GEARING Application filed March 6, 1929. Serial No. 344,644.

My invention relates to valve gearing and an object of my improvements is to provide an improved tappet or pusher-rod that will automatically compensate for the change in temperature and which may be readily adjusted to difierent conditions. I accomplish this object in the device illustrated in the accompanying drawing, in which:

Figure 1 is an elevation, mostly in section, of a pusher-rod embodying my invention, together with such adjacent parts as is necessary to illustrate the application of the invention. I

Figure 2 is a view, similar to Figure 1, 0 a modified construction omitting the cam shaft and cam.

Figure 3 is a plan View, partly in section, on the line IIIIII Figure 2.

2 is the cam shaft and 2a a cam thereon. 3 is the tappet or pusher-rod adapted to be actuated by the camQa. 4 is a valve stem. The pusher-rod 3 is hollow from its upper end to near its lower end and its interior wall is screwthreaded. Into the upper end of the cavity of the pusher rod 3 is screwed a hollow cylinder 5. This cylinder is also provided with screw-threads on its interior wall at its upper portion and into said cylinder is screwed the rod 6. Engaging screwthreads of the cylinders 5 and rod 6 form relatively movable engaging surfaces, the relative movement of which alters the total length of the valve actuating parts between the Valve actuating cam 2a and the valve 7 is a removable plug adapted to fit into the lower end of the cylinder 5 and carrying a spiral thermostat S engaged in a slot 78 in said plug. 9 is a pin securing the plug and thermostat 8 in place. The upper end of the thermostat 8 engages in a slot 68 in the lower end of the rod 6.

The modification shown in Figure 2 dispenses with the removable plug 7 and its thermostat and substitutes therefor a spiral thermostat 8c, the ends of which are eng ged by pins 68a and 85a, respectively, to the expanded outer end of the plug 6a and the upper end of the cylinder 5a.

It is well known that valve tappet clearance varies with the motor temperature and different motors have to have a different clearance, due to difference in cylinder and valve design.

Variation in temperature will deform the spiral 8 and 8a, turning the rod 6 or 6a to carry the same longitudinally in the pusherrod because of the engagement of its screwthreads in the cylinder 5 0r 5a. Different spirals for the thermostat and different pitches of screwthreads may be used to adapt p the devices for a special location and adjustment may be made by screwing the cylinder 5 or 5a out or in and fixing it in position by the jam-nut 53.

While I have described the embodiment of my invention in the tappet or pusher-rod, it will be understood that it is so placed solely because that element is interposed between the cam and the valve.

What I claim is:

1. A pusher-rod having an axial cylindrical aperture therein, a screwthreaded rod engaging screwthreads in said aperture and a thermostat engaging said rod and said pusherrod to turn said rod in said aperture.

2. The combination of a pusher-rod having a screw-threaded cylindrical aperture therein, a hollow cylindrical part having exterior and interior screwthreads, the exterior screwthreads engaging the screwthreads in said aperture in said pusher-rod, a screwthreaded rod engaging the screwthreads of the interior wall of said cylindrical part and a thermostat engaging said rod and said cylindrical part and adapted to turn said rod in said part.

3. In a valve gearing, a rigid means for transmitting the actuation to the valve said means having two relatively movable engag- 51 g eurtetee adapted alter the length f said means by their relative movement and a thermostat adapted to cause a relative movement of said surfaces to vary the length of said transmitting means.

4. In a valve gearing, a rigid rod for transmitting the actuation to the valve, said rod consisting of two parts united by screwthreads at their adjacent ends, a thermostat engaging both of said parts and adapted to cause a relative rotation of said parts to alter the length of said rod.

In testimony whereof I sign this specification. y I

HORACE T. THOMAS, 

